Despite the large number of patients with chronic low back pain there is little data on treatment effectiveness for this group. The authors of this feasibility study sought to answer some of the many questions on clinical management of chronic low back pain, including: "How do differences in the treatment processes relate to variations in outcomes among different types of practices and providers?" and "What is the relative benefit of different care strategies?"

In this study, forty-five chiropractors and thirty-three medical physicians collected data on patients with acute and chronic low back pain over a period of six months. This study dealt with the chronic low-back pain group consisting of 93 chiropractic patients and 45 medical patients. Physicians and patients completed questionnaires on the first visit. Follow up included a telephone interview with patients at seven to ten days, and a mailed questionnaire at one month and at three months. Physicians completed a follow up questionnaire on all subsequent visits. Patient questionnaires were administered in the waiting room before the first visit, and contained six parts. Socio-demographic information was collected. A condition specific questionnaire on low-back condition before treatment established baseline. A visual analog scale (VAS) measured pain severity. Pain quality was documented, and limitations on functional activities were assessed. General health was assessed using the Medical Outcomes Study 36-item Questionnaire (SF-36), with additional questions to screen for depression. The follow-up telephone interview included an assessment of patient satisfaction using a five point ordinal scale. The mailed follow up included a condition specific questionnaire, VAS, a questionnaire to document pain quality, and the functional limitation questionnaire.

Within the two provider groups patients differed in age, sex and employment status. Family practice physician patients tended to be older, female, less likely to be employed outside of the home, and less educated. Baseline measures of psychosocial health were similar for both groups but chronic depression of two years duration was seen in 31% of medical doctor patients compared to 14% of chiropractic patients. On general health measures at baseline, family practice patients tended to have poorer general health, with slightly greater physical impairment, and more bodily pain.

In general, chiropractic patients showed greater improvement than the medical patients at the one month follow up. Significant differences were seen in patient satisfaction, with chiropractic patients reporting greater satisfaction with information and treatment provided. The difference between the chiropractors and medical doctors was particularly evident in patient satisfaction with overall medical care. Of the patients that responded to the one-month mailed follow-up, 56% of chiropractic patients reported that their low back pain was better or much better, compared to only 13% of medical patients. Nearly one third of medical patients reported their low back pain as worse or much worse.

The authors conclude, "Patients with chronic low-back pain treated by chiropractors show greater improvement and satisfaction at 1 month than patients treated by family physicians." The researchers note that although there is, "...ample evidence in the literature to support a specific benefit from manipulation for patients with acute low-back presentation, there is a paucity of research on the benefit of manipulation for patients with chronic low-back pain." They hypothesize that:

"...outcome may be heavily influenced by the nature of the chiropractor-patient interaction, including more frequent visits and a process that engages the patient as a partner in the healing encounter."

"The influence of nonclinical factors appears to receive support from this study in that good outcome for medical patients was largely dependent on good psychological health at baseline, whereas the outcome for chiropractic patients was not. It may be that chiropractors dealt more effectively (successfully) with the psychosocial components of chronic low back pain..."

This feasibility study was limited in a few respects. There were fewer medical clinic patients enrolled than there were chiropractic patients; this is largely due to the complexities of multi-physician clinics, and did not affect patient characteristics. Self-selected treatment groups are known to be biased in observational studies, and not all patients responded to the one-month questionnaire. The authors state that their purpose was "...not to study efficacy as in a randomized clinical trial but to characterize patients and practices and to explore relationships at they exist in the community."